NASA's James Webb Space Telescope Discovers New Moon Orbiting Uranus

NASA announced that the James Webb Space Telescope has discovered a new, 29th satellite of Uranus, which was named S/2025 U1. With the James Webb Space Telescope, scientists from the Southwest Research Institute (SwRI) have discovered a previously unknown moon orbiting Uranus. This finding increases the planet's known satellite count to 29. The detection occurred on February 2, 2025, during an observation session led by Maryame El Moutamid.

The newly found moon, designated S/2025 U1, is estimated to be about 10 kilometres in diametre. Its small size likely made it invisible to previous missions like Voyager 2. "No other planet has as many small inner moons as Uranus," stated Matthew Tiscareno from the SETI Institute. He added that these moons' interactions with Uranus' rings suggest a complex history.

The observations were conducted using NIRCam's wide band F150W2 filter, capturing infrared wavelengths from approximately 1.0 to 2.4 microns. The animation created from this data shows the new moon alongside 13 of Uranus' other moons. Due to varying brightness levels, a composite of three treatments was used to highlight details in the atmosphere and surrounding rings.

The newly identified moon orbits about 56,000 kilometres from Uranus' centre. It lies between Ophelia and Bianca in the planet's equatorial plane. Its nearly circular orbit suggests it may have formed close to its current position. A name for this moon will need approval from the International Astronomical Union (IAU).

"Through this and other programmes, Webb is providing a new eye on the outer solar system," El Moutamid noted. The discovery is part of Webb's General Observer program, which allows global scientists to propose investigations using its advanced instruments. NIRCam's high resolution and infrared sensitivity are particularly effective at detecting faint objects beyond previous observatories' reach.

This discovery highlights modern astronomy's progress since Voyager 2 flew past Uranus on January 24, 1986. The James Webb Space Telescope continues to extend our understanding of distant celestial bodies nearly four decades later.